Semiconductor memory device having improved voltage transmission path and driving method thereof

ABSTRACT

Provided are a semiconductor memory device and a method of driving the device which can improve a noise characteristic of a voltage signal supplied to a memory cell of the device. The semiconductor memory device includes a first semiconductor chip and one or more second semiconductor chips stacked on the first chip. The first chip includes an input/output circuit for sending/receiving a voltage signal, a data signal, and a control signal to/from an outside system. The one or more second semiconductor chips each include a memory cell region for storing data. The second semiconductor chips receive at least one signal through one or more signal paths that are formed outside the input/output circuit of the first chip.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefit of Korean Patent Application No.10-2006-0117087, filed on Nov. 24, 2006, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND

1. Field of the Invention

The present invention relates to a semiconductor memory device and adriving method thereof, and more particularly, to a semiconductor memorydevice and a driving method thereof that are capable of improving anoise characteristic of a voltage signal provided to a memory cell ofthe semiconductor memory device.

2. Description of the Related Art

In recent years, the capacity and speed of memory chips, which are usedas memory devices in electronic systems, have increased. Furthermore,various attempts to increase memory capacity per unit area and to drivethe memory more rapidly have been made.

FIG. 1 is a schematic view of a general conventional semiconductor chip10. Referring to FIG. 1, the semiconductor chip 10 includes an I/Oregion 11, which includes an input/output circuit for sending/receivingdata signals and control signals, etc. to/from an outside system, andcell regions 12, which include memory cells for storing the data.

Generally, the semiconductor chip 10 has a structure in which the I/Oregion 11 is disposed in a central region of the semiconductor chip 10and the cell regions 12 are disposed on both sides of the I/O region 11.The I/O region 11 includes one or more pads PAD, where voltage signals,data signals, and control signals, etc. are inputted from the outsidesystem via the pads PAD. In order to store or read the data, the voltagesignals, the data signals, and the control signals are supplied to thecell regions 12 through the input/output circuit of the I/O region 11.

In the semiconductor chip 10, the area of the cell regions 12 occupiesmost of the chip area, and paths of the power supply voltage and theground voltage supplied to the memory cells pass through the I/O region11 in the center of the semiconductor chip 10. In a general case, thepower supply voltage and the ground voltage are applied to asemiconductor package on which the semiconductor chip 10 is mountedthrough solder balls disposed on an outer surface of the semiconductorpackage. However, in this configuration, a feed/sink path of the voltagesignals becomes relatively long, which hampers performancecharacteristics of the chip 10.

FIG. 2 is a cross-sectional view of a general conventional semiconductorpackage that illustrates a path of a voltage signal transferred to thesemiconductor chip. Referring to FIG. 2, the semiconductor package mayinclude one or more semiconductor chips having a stacked structure, anda package substrate 30 for mounting the stacked semiconductor chips.

FIG. 2 illustrates a case where two semiconductor chips are stacked asan example of a conventional semiconductor package. In addition, thesemiconductor package illustrates an example in which one or moresemiconductor chips are packaged in a wafer stack form. The twosemiconductor chips include I/O regions 11 and 21, respectively, whichare positioned in the center of the package substrate 30, and cellregions 12 and 22 which are disposed on both sides of the I/O regions 11and 21, respectively.

A power supply voltage or a ground voltage that is transferred from oneor more solder balls mounted on the bottom surface of the packagesubstrate 30 through the I/O regions 11 and 21 to reach the cell regions12 and 22. The power supply voltage or the ground voltage is inputted toan input/output circuit included in the I/O regions 11 and 21 and isthen supplied from the input/output circuit to the cell regions 12 and22. An arrow indicated in FIG. 2 shows a path through which the voltagesignal from the solder balls attached to the outer surface of thepackage substrate 30 is supplied to the cell region 12.

In order to supply the voltage signal from the I/O regions 11 and 21 tothe cell regions 12 and 22, aluminum wiring, which has a relativelylarge resistance, is generally used. As FIG. 2 shows, this path canbecome relatively long. This length coupled with the large resistance ofthe wiring path can generate noise in the voltage signal provided to thecell regions 12 and 22. As a result, the performance of the entirememory system deteriorates.

SUMMARY

Embodiments of the present invention provide a semiconductor memorydevice and a driving method thereof which are capable of providing astable voltage signal to a memory cell of the semiconductor memorydevice.

According to an embodiment of the present invention, a semiconductormemory device includes a first semiconductor chip and one or more secondsemiconductor chips stacked on the first chip. The first semiconductorchip includes an input/output circuit for sending/receiving a voltagesignal, a data signal, and a control signal to/from an outside system.The one or more second semiconductor chips each include a memory cellregion for storing data. The second semiconductor chips receive at leastone signal through one or more signal paths that are formed outside theinput/output circuit of the first semiconductor chip.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a schematic view of a general conventional semiconductor chipstructure;

FIG. 2 is a cross-sectional view of a general conventional semiconductorpackage that illustrates a path through which a voltage signal istransferred to a semiconductor chip;

FIG. 3 is a cross-sectional view of a semiconductor memory deviceaccording to an embodiment of the present invention;

FIG. 4 illustrates a via structure which is formed in the semiconductormemory device illustrated in FIG. 3, according to an embodiment of thepresent invention;

FIG. 5 is a cross-sectional view of a semiconductor memory deviceaccording to another embodiment of the present invention;

FIG. 6 illustrates a via structure which is formed in the semiconductormemory device illustrated in FIG. 5, according to an embodiment of thepresent invention;

FIG. 7 is a cross-sectional view of a high-capacity semiconductor memorydevice according to an embodiment of the present invention; and

FIG. 8 is a flowchart illustrating a method of driving a semiconductormemory device according to an embodiment of the present invention.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as being limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. In thedrawings, the thickness of layers and regions are exaggerated forclarity. Like numbers refer to like elements throughout thespecification.

FIG. 3 is a cross-sectional view of a semiconductor memory device 100according to an embodiment of the present invention. The semiconductormemory device 100 shown in a packaged form may include a firstsemiconductor chip 110 that includes an input/output circuit forsending/receiving a voltage signal, a data signal and a control signal,etc. to/from the outside system. The semiconductor memory device 100 mayalso include one or more second semiconductor chips 120, each of whichincludes a memory cell region for storing data. Although twosemiconductor chips are illustrated in FIG. 3, one, two, or more secondsemiconductor chips 120 may be stacked on the first semiconductor chip110.

In other words, although the input/output circuit and memory cells areincluded in one chip in the prior art, the embodiment of the presentinvention illustrated in FIG. 3 includes at least two separatesemiconductor chips, where a first semiconductor chip 110 includes aninput/output circuit and one or more second semiconductor chips includememory cells.

Referring again to FIG. 3, the semiconductor memory device 100 mayinclude a package substrate 130 for stacking the first semiconductorchip 110 and the second semiconductor chip 120 on a first side (e.g.,the upper surface) and one or more solder balls 140 attached to a secondside (e.g., the bottom surface) of the package substrate 130 forelectrically connecting the first and second semiconductor chips to anoutside system. A circuit pattern (or wiring) is formed in the packagesubstrate 130 to transfer the signals inputted through the solder balls(or connection terminals) 140 to the first and second semiconductorchips. In addition, the solder balls 140 may include one or more solderballs dedicated to supplying a power supply voltage VDD and one or moresolder balls dedicated to supplying a ground voltage VSS to thesemiconductor memory device 100.

The first semiconductor chip 10 includes an active region 110_1 in whichthe input/output circuit is actually disposed. Since the area of theinput/output circuit is smaller than that of the memory cell region ofthe second semiconductor chip 120, the active region 110_1 isimplemented so as to be smaller than the second semiconductor chip 120.

In order to smoothly transfer the signals between the firstsemiconductor chip 110 and the second semiconductor chip 120, the firstsemiconductor chip 110 may include an overhead region 110_2 in which atleast one conductive means is formed. The overhead region 110_2 may bedisposed on both sides of the active region 110_1, and the firstsemiconductor chip 110 including the active region 110_1 and theoverhead region 110_2 may be manufactured so as to be substantiallyequal in size to the second semiconductor chips 120.

The voltage signal, the data signal and the control signal are inputtedto the first and second semiconductor chips 110 and 120 via a packagesubstrate 130 and a solder ball 140. The inputted data signal andcontrol signal are supplied to the second semiconductor chip 120 so thatread and write operations on the memory cell are performed. On the otherhand, the inputted voltage signal is used as a power supply for drivingthe first and second semiconductor chips 110 and 120.

As shown in FIG. 3, at least one of these signals can be inputted to thesecond semiconductor chip 120 through a separate electrical path formedoutside the active region 110_1 of the first semiconductor chip 110. Itmay be especially beneficial to input the power supply Vdd and/or theground voltage Vss though the separate electrical path or separateelectrical paths because these voltage signals can be directly routed tothe memory cells without passing through the input/output circuit in theactive region 110_1 of the first semiconductor chip 110.

To this end, at least one conductive means is formed in the overheadregion 110/_2 of the first semiconductor chip 110. This at least oneconductive means may be implemented as one or more vias. A conventionalwafer through-via forming process may be used to form the vias. Some ofthe vias formed in the overhead region 110_2 may be electricallyconnected to the solder ball for supplying the power supply voltage VDD,and other vias may be electrically connected the solder ball forsupplying the ground voltage VSS.

Additionally, the second semiconductor chip 120 may include at least oneconductive means to which the voltage signal inputted through the via istransferred into the second semiconductor chip 120. The one or more viasmay also pass through a second semiconductor chip 120 to reach anothersecond semiconductor chip 120 above it. A first via may be formed in thesecond semiconductor chip 120 and connected to the via which is formedin the overhead region 110_2 to transfer the power supply voltage VDD.In addition, a second via may be connected to the via which is formed inthe overhead region 110_2 to transfer the ground voltage VSS.

On the other hand, a third via for receiving the data signal and thecontrol signal etc. may be further formed in the second semiconductorchip 120. When the first semiconductor chip 110 and the secondsemiconductor chip 120 are stacked, the third via may be formed in aregion corresponding to the active region 110_1 of the firstsemiconductor chip 110. The third via may be electrically connected tothe input/output circuit, and the data and the control signal may besupplied to the memory cell included in the second semiconductor chip120 through the third via.

In addition, when forming the first via and the second via in the secondsemiconductor chip 120, the vias may be formed at positionscorresponding to the vias formed in the overhead region 110_2 of thefirst semiconductor chip 110. As an example, when the firstsemiconductor chip 110 and the second semiconductor chip 120 arestacked, the first via may be formed at a position which corresponds toa fourth via within the overhead region 110_2 to be electricallyconnected to the power supply voltage VDD. The second via may also beformed at a position which corresponds to a fifth via within theoverhead region 110_2 to be electrically connected to the ground voltageVSS.

According to an embodiment of the present invention, the input/outputcircuit and the memory cells are implemented as separate chips.Additionally, the power supply voltage and the ground voltage which aresupplied to the memory cell may be transferred through separate pathswhich are formed outside the input/output circuit. Accordingly, a feedpath of the power supply voltage and a sink path of the ground voltageof the power supply voltage can be reduced, so that voltage noise whichis generated in the input/output circuit and the memory cells do notaffect each other.

In addition, since the input/output circuit and the memory cells areimplemented as separate chips, memory devices which operate in differentoperating modes, such as DDR1, DDR2, and GDDR etc. in accordance withthe characteristic of the semiconductor chip which includes theinput/output circuit, may be implemented. FIG. 3 illustrates an examplein which a plurality of chips are mounted in the substrate in a flipchip configuration. However, the present invention is not limited tothis configuration. Alternatively, the plurality of chips may beconnected to each other through wire bonding, or each chip may be formedas an independent package by attaching solder balls to the chip.

FIG. 4 illustrates a via structure which is formed in the semiconductormemory device 100 illustrated in FIG. 3, according to an embodiment ofthe present invention. The first semiconductor chip 110 and the secondsemiconductor chip 120 are illustrated in FIG. 4.

Referring to FIG. 4, the first semiconductor chip 110 may include theactive region 110_1 and the overhead region 110_2. A predeterminedinput/output circuit (not shown), one or more pads PAD, and one or moreconductive means 113 may be included in the active region 110_1. Inaddition, one or more conductive means 111 and 112 may be included inthe overhead region 110_2. A wafer through via is shown as an example ofthe conductive means 111 through 113.

A pattern (not shown) for transferring the voltage to the memory cell isformed in the second semiconductor chip 120, and the secondsemiconductor chip 120 includes one or more conductive means, such asfirst vias 121 through third vias 123, for receiving the voltage signal,the data signal, and the control signal, etc. When the firstsemiconductor chip 110 and the second semiconductor chip 120 arestacked, the first vias 121 and the second vias 122 are positioned abovethe overhead region 110_2 of the first semiconductor chip 110, and thethird vias 123 are positioned above the active region 110_1 of the firstsemiconductor chip 110.

The first vias 121 of the second semiconductor chip 120 are electricallyconnected to fourth vias 111 of the first semiconductor chip 110. Inaddition, the fourth vias 111 are electrically connected to a powersupply voltage VDD through the solder ball and a substrate (130 in FIG.3) of a semiconductor package. Accordingly, the power supply voltage VDDmay be inputted to the first vias 121 through the fourth vias 111 tosupply the power supply voltage VDD to the memory cell.

Additionally, the second vias 122 of the second semiconductor chip 120are electrically connected to a fifth via 112 of the first semiconductorchip 110. In addition, the fifth via 112 is electrically connected theground voltage VSS through the solder ball and the substrate (130 inFIG. 3) of the semiconductor package. Accordingly, the ground voltageVSS may be inputted to the second vias 122 through the fifth vias 112 tosupply the ground voltage VSS to the memory cell.

The third vias 123 of the second semiconductor chip 120 are electricallyconnected to the input/output circuit through vias 113 which are formedin the active region 110_1 of the first semiconductor chip 110.Accordingly, the data signal and the control signal may be inputted fromthe input/output circuit and to perform a read/write operation on thememory cell.

FIG. 5 is a cross-sectional view illustrating a semiconductor memorydevice 200 according to another embodiment of the present invention.Referring to FIG. 5, the semiconductor memory device 200 may include afirst semiconductor chip 210 that includes an input/output circuit forsending/receiving a voltage signal, a data signal, and a control signalto/from the device, and one or more second semiconductor chips 220, eachof which includes a memory cell region for storing data. In addition,the semiconductor memory device 200 may include a package substrate 230for stacking the first semiconductor chip 210 and the secondsemiconductor chip 220 on a first side (e.g., the upper surface), andone or more first solder balls 240 attached to a second side (e.g., thebottom surface) of the package substrate 230 for electrically connectingthe semiconductor chips to an outside system. The semiconductor memorydevice 200 operates in a similar way to the semiconductor memory device100 illustrated in FIG. 3, and thus a detailed description thereof willbe omitted.

FIG. 5 illustrates an example in which the chips in the package areimplemented as a wafer stack, and in the present embodiment, the firstsemiconductor chip 210 comprises only an active region. One or more viasare formed in the first semiconductor chip 210, and the data signal, thecontrol signal, and the voltage signal, etc. for the first semiconductorchip 210 can be transferred through the vias.

On the other hand, the voltage signals, such as the power supply voltageVDD and the ground voltage VSS etc. which are supplied to the memorycell may be supplied to the second semiconductor chip 220 throughseparate paths which do not pass through the first semiconductor chip210. As an example, the second semiconductor chip 220 may include atleast one conductive means which is composed of vias etc. passingthrough the first semiconductor chip 210, and at least one conductivemeans disposed outside the edge boundaries of the first chip 210 on thepackage substrate 230. Specifically, the semiconductor memory device 200further includes a conductive means which is positioned at the outsideof the first semiconductor chip 210. This conductive means may beimplemented as one or more second solder balls 250. The vias which areformed in the second semiconductor chip 220 and the package substrate230 may be electrically connected to each other through a plurality ofthe second solder balls 250.

Some of the plurality of second solder balls 250 may be connected to thepower supply voltage Vdd through the first solder balls 240 connected tothe outside system and the package substrate 230. In addition, othersolder balls of the second solder balls 250 may be electricallyconnected to some of the vias formed in the second semiconductor chip220 so that the power supply voltage VDD can be supplied to the memorycell. In addition, separate solder balls of the second solder balls 250may be connected to the ground voltage Vss through the first solderballs 240 connected to the outside system and the package substrate 230.Furthermore, other solder balls may be connected to other vias formed inthe second semiconductor chip 220 so that the ground voltage Vss can besupplied to the memory cell.

When constructed as described above, the first semiconductor chip 210does not include the overhead region, so that the size of the firstsemiconductor chip can be decreased. As a result, there is an advantagein that the semiconductor chips that include more the input/outputcircuits in the same wafer can be obtained by with a decrease in thesize of the first semiconductor chip 210.

FIG. 6 shows a via structure which is formed in the semiconductor memorydevice 200 illustrated in FIG. 5, according to an embodiment of thepresent invention. As shown in FIG. 5, the first semiconductor chip 210includes only the active region in which the input/output circuit (notshown) is disposed. The first semiconductor chip 210 may include one ormore pads PADs and one or more conductive means 211. The conductivemeans 211 may comprise one or more vias, and the data signal, thecontrol signal, and the voltage signal for the first semiconductor chip210 etc. may be transferred through the vias.

Additionally, a pattern for transferring the voltage to the memory cellsis formed in the second semiconductor chip 220, where the secondsemiconductor chip 220 includes one or more conductive means, such asfirst vias 221 through third vias 223 for receiving the voltage signal,the data signal, and the control signal, etc. One or more first vias 221and one or more second vias 222 may be connected to the solder balls 250as illustrated in FIG. 5 to thereby supply the power supply voltage VDDand the ground voltage VSS into the second semiconductor chip 220,respectively. On the other hand, one or more third vias 223 may beconnected to the input/output circuit of the first semiconductor chip210 to thereby supply the data signal and the control signal into thesecond semiconductor chip 220.

FIG. 7 is a cross-sectional view illustrating a high-capacitysemiconductor memory device 300 according to an embodiment of thepresent invention. Referring to FIG. 7, a plurality of semiconductorchips are mounted in a stacked structure in the semiconductor memorydevice 300 according to the current embodiment of the present invention.In the semiconductor memory device 300 illustrated in FIG. 7, foursemiconductor chips are mounted in a wafer stack structure. However, thepresent invention is not limited thereto, and it is obvious that moresemiconductor chips can be mounted in the package.

The semiconductor memory device 300 may include a first semiconductorchip 310 including an input/output circuit, and one or more secondsemiconductor chips 320 each of which includes a memory cell region. Thesemiconductor memory device 300 may also include a package substrate 330for stacking the first semiconductor chip and the second semiconductorchips, and one or more solder balls 340 for electrically connecting thefirst semiconductor chip and the second semiconductor chips to anoutside system. As shown in FIG. 7, the first semiconductor chip 310 mayinclude both an active region and an overhead region; however, asdescribed above, the first semiconductor chip 310 may include only theactive region. In this case, an additional connection means is requiredfor electrically connecting the second semiconductor chips 320 to thepackage substrate 330.

Additionally, at least one via is formed in each of the plurality ofsecond semiconductor chips 320. When the plurality of secondsemiconductor chips 320 are stacked, the via may be formed in the sameposition in each of the semiconductor chips so as to be in alignment.

FIG. 8 is a flowchart illustrating a method of driving a semiconductormemory device according to an embodiment of the present invention.Referring to FIG. 8, in the driving method, the power supply voltageand/or the ground voltage supplied from the outside system aretransferred to the package substrate (step S11).

The voltage signal transferred to the package substrate is thentransferred into the inside of the package through the first conductivemeans (e.g., vias) that are included in the overhead region of the firstsemiconductor chip including the input/output circuit. Alternatively,the first conductive means may be implemented as one or more solderballs formed outside the first semiconductor chip where the first chipdoes not have an overhead region (step S12). More particularly, thevoltage signals for supplying power and/or ground voltages to the memorycells are transferred through first conductive means as described above.

The first conductive means is electrically connected to a secondconductive means formed in the second semiconductor chip including thememory cell region. Accordingly, the voltage signal is transferred tothe second conductive means through the first conductive means (stepS13). The voltage signal that is transferred to the second conductivemeans is supplied to the memory cell through a pattern formed in thesecond semiconductor chip (step S14).

In the semiconductor memory device according to the present invention,an input/output circuit and a memory cell can be implemented in separatesemiconductor chips and a voltage signal can be directly supplied to thememory cell so that a stable voltage signal by which noise is reducedcan be supplied to the memory cell.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims. Therefore,the true technical protection scope of the present invention should bedefined by the technical spirit of appended claims.

1. A semiconductor memory device comprising: a first semiconductor chipcomprising an input/output circuit for sending/receiving signals to/froman outside system; and at least one second semiconductor chip comprisinga memory cell region for storing data, wherein the second semiconductorchip receives at least one signal through a signal path formed outsidethe input/output circuit.
 2. The device of claim 1, wherein the firstsemiconductor chip and the second semiconductor chip have a stackstructure.
 3. The device of claim 1, wherein the second semiconductorchip receives a voltage signal through the signal path.
 4. The device ofclaim 3, wherein the second semiconductor chips comprises one or morevias for transferring the voltage signal into the second semiconductorchip.
 5. The device of claim 4, wherein the second semiconductor chipcomprises one or more first vias for transferring a power supplyvoltage, and one or more second vias for transferring a ground voltage.6. The device of claim 5, wherein the second semiconductor chip furthercomprises one or more third vias for receiving a data signal and acontrol signal, the data signal and control signal transferred throughthe input/output circuit.
 7. The device of claim 6, wherein the firstsemiconductor chip comprises an active region and an overhead region,the active region including the input/output circuit, and the overheadregion including at least one conductive means.
 8. The device of claim7, wherein the conductive means comprises a fourth via electricallyconnected to the first via, and a fifth via electrically connected tothe second via.
 9. The device of claim 8, wherein the firstsemiconductor chip and the second semiconductor chip are stacked, thefourth via substantially vertically aligned with the first via, and thefifth via substantially vertically aligned with the second via.
 10. Thedevice of claim 9, wherein the power supply voltage is transferred tothe second semiconductor chip through the fourth via, and the groundvoltage is transferred to the one or more second semiconductor chipsthrough the fifth via.
 11. A semiconductor memory device comprising: afirst semiconductor chip comprising an input/output circuit forsending/receiving a voltage signal, a data signal, and a control signalto/from an outside system; one or more second semiconductor chips eachcomprising a memory cell region for storing data; a package substratehaving a first side and a second side, wherein the first semiconductorchip and the second semiconductor chips are stacked on the first side ofthe package substrate in order to connect the first semiconductor chipand the second semiconductor chips to an outside system; and aconductive means configured to electrically connect the one or moresecond semiconductor chips to the package substrate, the conductivemeans disposed outside the first semiconductor chip, wherein the secondsemiconductor chips receive at least one signal through the conductivemeans.
 12. The device of claim 11, wherein the conductive meanscomprises one or more solder balls attached between the one or moresecond semiconductor chips and the first side of the package substrate.13. The device of claim 11, wherein the second semiconductor chipsreceive a power supply voltage and/or a ground voltage through theconductive means.
 14. The device of claim 11, wherein each of the one ormore second semiconductor chips comprises one or more vias connected tothe conductive means to supply a signal transferred through theconductive means into the second semiconductor chips.
 15. The device ofclaim 14, wherein each of the one or more second semiconductors chipcomprises one or more first vias to transfer a power supply voltage, andone or more second vias to transfer a ground voltage.
 16. A method ofdriving a semiconductor memory device comprising: transferring a powersupply voltage and/or a ground voltage supplied from an outside systemto a package substrate; transferring the power supply voltage and/or theground voltage into a package through a first conductive means disposedoutside an input/output circuit included in a first semiconductor chip;and supplying the power supply voltage and/or the ground voltage to oneor more second semiconductor chips each of which comprises a memory cellregion for storing data, wherein the one or more second semiconductorchips transfer the power supply voltage and/or the ground voltage intothe second semiconductor chips using a second conductive meanselectrically connected to the first conductive means.
 17. The method ofclaim 16, wherein the first semiconductor chip comprises an activeregion and an overhead region, the active region includes theinput/output circuit, and the overhead region includes the firstconductive means; and wherein the first conductive means includes one ofmore vias and electrically connects the package substrate to the one ormore second semiconductor chips.
 18. The method of claim 17, wherein thefirst conductive means includes one or more solder balls formed outsidethe first semiconductor chip to electrically connect the packagesubstrate to the one or more second semiconductor chips.
 19. The methodof claim 18, wherein the second conductive means includes one or morefirst vias for transferring the power supply voltage and one or moresecond vias for transferring the ground voltage.
 20. The method of claim17, wherein the first conductive means includes one or more first viasfor transferring the power supply voltage and one or more second viasfor transferring the ground voltage.
 21. A semiconductor memory devicecomprising: a package substrate having a first side and a second side,the package substrate including wiring formed in the package substrate;connection terminals disposed on the second side of the packagesubstrate, the connection terminals electrically connected to the wiringin the package substrate; a first semiconductor chip disposed on thefirst side of the package substrate, the first semiconductor chipincluding an input/output circuit for sending/receiving a voltagesignal, a data signal, and a control signal to/from an outside system,wherein the input/output circuit is in an active region at asubstantially central portion of the first semiconductor chip; at leastone second semiconductor chip stacked on the first semiconductor chip,the second semiconductor chip comprising a memory cell region in aperipheral portion of the second semiconductor chip for storing data;and a conductive means configured to electrically connect the secondsemiconductor chip to the wiring in the package substrate, theconductive means disposed outside the active region of the firstsemiconductor chip that includes the input/output circuit, wherein thesecond semiconductor chips receive at least one of a power supply signaland a ground signal through the conductive means.
 22. The device ofclaim 21 wherein the connection means includes solder balls formedbetween the first side of the package substrate and a bottommost secondsemiconductor chip.
 23. The device of claim 21 wherein the connectionmeans includes vias formed in an overhead region of the firstsemiconductor chip outside of the active region.
 24. The device of claim21 wherein a signal path from the connection terminals to the memorycell region of the second memory chip through the conductive means issubstantially shorter than a signal path from the connection terminalsto the memory cell region of the second memory chip through theinput/output circuit of the first memory chip.
 25. The device of claim21, wherein the at least one second semiconductor chip includes twostacked semiconductor memory chips.
 26. The device of claim 25, whereina lower one of the two stacked semiconductor memory chips includes a viato electrically connect the conductive means to the memory cell regionof an upper one of the two stacked semiconductor memory chips.